The training of a surgeon requires the acquisition of a number of characteristics. These include a knowledge base (cognitive), problem formulation, decision processing, psychosocial relationships and others that can be evaluated and graded by objective testing such as National Board or Specialty Certifying examinations. Critical to the surgeon are the technical skills that are at the core of the profession. This proposal responds to the need to create a battery of sophisticated devices and objective measurements to teach and evaluate the inherent technical ability of trainees. We hypothesize that by innovative, state- of-the-art simulation, devices that train both surgical tasks and skills through repetitive proctored challenges, without risk to patients, will allow for detection and analysis of surgical errors and "near misses". In an analogy to flight simulation, "near miss" detection is where potential errors are found and complications prevented Using a number of otolaryngology residencies, a controlled training curriculum will be developed based on complimentary simulation tools [the endoscopic sinus surgery simulator (ES3), minimally invasive surgical trainer - virtual reality (MIST VR), perceptual and 3- dimensional testing] with objective metrics used for assessment of trainees. Technical errors will be identified, quantified and used to train and monitor surgical performance and for outcomes analysis to improve patient safety. Some current validated metrics include: time- to-completion, errors, economy of motion and psychomotor tracking. Correlation with psychometric parameters (perception, psychomotor, visio-spatial, cognitive mapping, etc.) will be used to identify technical errors and to validate both the simulator and the curriculum. The collaborating investigators and institutions have expertise in the areas of metrics, curriculum, database development, simulator creation and modification, and outcomes analysis. Endoscopic sinus surgery is the operation substrate since it is frequently performed (greater than 300,000 procedures annually) and carries a significant risk of injury to the contiguous structures ofthe eye (loss of vision and /or eye motion) and brain (CSF leakage, meningitis, death). The ES3 is also the most advanced surgical simulation device existing and based largely on jet pilot flight simulation (Lockheed Martin).